Update InitializableAdminUpgradeabilityProxy.sol

contracts/open-zeppelin/InitializableAdminUpgradeabilityProxy.sol

@@ -6,31 +6,41 @@ import "./InitializableUpgradeabilityProxy.sol";
 
 /**
  * @title InitializableAdminUpgradeabilityProxy
- * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for 
- * initializing the implementation, admin, and init data.
+ * @dev Extends BaseAdminUpgradeabilityProxy with an initializer for
+ *      setting the implementation, admin, and initialization data.
  */
-contract InitializableAdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, InitializableUpgradeabilityProxy {
-    /**
-   * Contract initializer.
-   * @param _logic address of the initial implementation.
+contract InitializableAdminUpgradeabilityProxy is
+  BaseAdminUpgradeabilityProxy,
+  InitializableUpgradeabilityProxy
+{
+  /**
+   * @notice Contract initializer.
+   * @param _logic Address of the initial implementation.
    * @param _admin Address of the proxy administrator.
    * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
-   * It should include the signature and the parameters of the function to be called, as described in
-   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
-   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
+   *        It should include the signature and the parameters of the function to be called, as described in
+   *        https://docs.soliditylang.org/en/v0.6.12/abi-spec.html#function-selector-and-argument-encoding.
+   *        This parameter is optional; if no data is provided, the initialization call to the proxied contract will be skipped.
    */
-    function initialize(address _logic, address _admin, bytes memory _data) public payable {
-        require(_implementation() == address(0));
-        InitializableUpgradeabilityProxy.initialize(_logic, _data);
-        assert(ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
-        _setAdmin(_admin);
-    }
-
-    /**
-    * @dev Only fall back when the sender is not the admin.
-    */
-    function _willFallback() internal override(BaseAdminUpgradeabilityProxy, Proxy) {
-        BaseAdminUpgradeabilityProxy._willFallback();
-    }
+  function initialize(
+    address _logic,
+    address _admin,
+    bytes memory _data
+  ) public payable {
+    require(_implementation() == address(0), "Already initialized");
+    InitializableUpgradeabilityProxy.initialize(_logic, _data);
+    // EIP-1967 admin slot check
+    assert(ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
+    _setAdmin(_admin);
+  }
 
+  /**
+   * @dev Only fallback when the sender is not the admin.
+   */
+  function _willFallback()
+    internal
+    override(BaseAdminUpgradeabilityProxy, Proxy)
+  {
+    BaseAdminUpgradeabilityProxy._willFallback();
+  }
 }